Optimising liquid production of the insect pathogenic fungus Metarhizium anisopliae and enhancing the shelf life of blastospores.

Abstract

There is much interest in the development of insect pathogenic fungi like Metarhizium anisopliae as environmentally friendly alternatives to chemical pesticides. One of the major hurdles in the commercialisation of fungal biological control agents is production cost. An earlier 'Follow-On' NERC grant (NE/E522308/1) showed that M. anisopliae strains V275, 3297 and 4556 are highly stable (retaining their virulence upon repeated in vitro sub-culturing), and produce high yields of aerial conidia on broken rice. Recently, we found that these strains produced blastospores in liquid media. This creates the opportunity for mass production in liquid media which would reduce production costs further and generate highly competitive Metarhizium-based products. Blastospores are thin walled infection propagules which are less robust and have a shorter shelf life than aerial conidia (1-3 days versus several months at room temperature). The yield, virulence and shelf life of fungal propagules can be improved by manipulating nutrients and media water activity. The aims of this project are to develop media to (i) increase yields of M. anisopliae blastospores, (ii) demonstrate upscaled production without loss of quality and (iii) to develop formulations to enhance blastospore shelf life. Overall, the proposed work will reduce production costs and accelerate development of highly competitive commercial products based on M. anisopliae blastospores for control of a range of arthropod pests (e.g. vine weevil, thrips, ticks).